IN 10,000 years,
the earth's population has doubled ten times, from less than 10m to more
than six billion now and ten billion soon. Most of the calories that made
that increase possible have come from three plants: maize, rice and wheat.
The oldest, most widespread and until recently biggest of the three crops
is wheat (see chart). To a first approximation wheat is the staple food of
mankind, and its history is that of humanity.

Yet today, wheat
is losing its crown. The tonnage (though not the acreage) of maize
harvested in the world began consistently to exceed that of wheat for the
first time in 1998; rice followed suit in 1999. Genetic modification,
which has transformed maize, rice and soyabeans, has largely passed wheat
by—to such an extent that it is in danger of becoming an “orphan crop”.
The Atkins diet and a fashion for gluten allergies have made wheat seem
less wholesome. And with population growth rates falling sharply while
yields continue to rise, even the acreage devoted to wheat may now begin
to decline for the first time since the stone age.

It is time to
pay tribute to this strange little grass that has done so much for the
human race. Strange is the word, for wheat is a genetic monster. A typical
wheat variety is hexaploid—it has six copies of each gene, where most
creatures have two. Its 21 chromosomes contain a massive 16 billion base
pairs of DNA, 40 times as much as rice, six times
as much as maize and five times as much as people. It is derived from
three wild ancestral species in two separate mergers. The first took place
in the Levant 10,000 years ago, the second near the Caspian Sea 2,000
years later. The result was a plant with extra-large seeds incapable of
dispersal in the wild, dependent entirely on people to sow them.

The story
actually starts much earlier, around 12,000 years ago. At the time, after
several warm millennia, a melting ice sheet in North America collapsed and
a gigantic lake drained into the North Atlantic through the St Lawrence
seaway. The torrent of cool, fresh water altered the climate so
drastically that the ice age, which had been in full retreat, resumed for
a further 11 centuries. The Scandinavian ice sheet surged south. Western
Asia became not only cooler, but much drier. The Black Sea all but dried
out.

People in what
is now Syria had been subsisting happily on a diet of acorns, gazelles and
grass seeds. The centuries of drought drove them to depend increasingly on
wild grass seeds. Abruptly, soon after 11,000 years ago, they began to
cultivate rye and chickpeas, then einkorn and emmer, two ancestors of
wheat, and later barley. Soon cultivated grain was their staple food. It
happened first in the Karacadag Mountains in south-eastern Turkey—it is
only here that wild einkorn grass contains the identical genetic
fingerprint of modern domesticated wheat.

Who first
replanted the seeds and why? For a start, he was probably a she: women
have primary responsibilities for plant gathering in hunter-gatherer
societies. The time was certainly ripe for agriculture: the ability to
make tools and control fire (cooking makes many plants more digestible)
was already well established. But was it an act of inspiration or
desperation? Did it perhaps happen by accident, as discarded grains
germinated around human settlements?

The wheat plant
evolved three new traits to suit its new servants: the seeds grew larger;
the “rachis” which binds the seeds together became less brittle so whole
ears of grass, rather than individual seeds, could be gathered; and the
leaf-like glumes that covered each seed loosened, thus making the grains
“free-threshing”. In the past two years, the very mutations that allowed
these changes have been located within the wheat plant's genome.

Wheat's servants
now became its slaves. Agriculture brought drudgery, subjugation and
malnutrition, because unlike hunter-gatherers, farmers could eke out a
living when times were bad. But at least that meant that they could
survive. Population growth was now inevitable. Within a few generations,
wheat farmers were on the march, displacing and overwhelming
hunter-gatherers as they went, and bringing with them their distinct
Indo-European language, of which Sanskrit and Irish are both descendants.
By 5,000 years ago wheat had reached Ireland, Spain, Ethiopia and India. A
millennium later it reached China: paddy rice was still thousands of years
in the future.

Wherever they
went, the farmers brought their habits: not just sowing, reaping and
threshing, but baking, fermenting, owning, hoarding. By 9,000 years ago
they had domesticated cattle, to which they could feed wheat to get meat
and milk. They could also get precious manure to fertilise the fields. Not
until 6,000 years ago did somebody invent the first plough to turn the
earth, burying weeds and breaking up the seedbed.

Innovations came
slowly in wheat farming. The horse collar arrived in the third century
BC, in China. By not pressing on the animal's
windpipe, it enabled the animal to drag greater weight—and faster than an
ox. In 1701 AD the Berkshire farmer Jethro Tull
devised a simple seed drill based on organ pipes, which resulted in eight
times as many grains harvested for every grain sown. Like most
agricultural innovators since, he was vilified. A century later the
threshing machine was greeted by riots.

In 1815 a
gigantic volcanic eruption at Tambora in Indonesia led to the famous “year
without a summer”. New England had frosts in July. France had bitter cold
in August. Wheat prices reached a level that would never be seen again in
real terms, nearly $3 a bushel. Thomas Robert Malthus was then at the
height of his fame and the harvest failure seemed to bear out his
pessimism. In 1798 he had forecast a population crash, based on the
calculation that it was impossible to improve wheat yields as fast as
people made babies (each new baby can make more babies; each new field of
grain leaves less new land to cultivate).

The Malthusian
crash was staved off in the 19th century by bringing more land under the
plough—in North America, Argentina and Australia especially. But wheat
yields per acre grew worse if anything as soil nutrients were depleted. So
in 1898, in a speech to the British Association, a chemist, Sir William
Crookes, argued again that worldwide starvation was inevitable within a
generation. Population was rising fast. There was little new land to
plough. Famines became worse each season, especially in Asia.

This time it was
the tractor that averted Malthusian disaster. The first tractors had few
advantages over the best horses, but they did not eat hay or oats. The
replacement of draft animals by machines released about 25% more land for
growing food for human consumption.

The Malthusian
limit would surely be reached one day, though. The only way to increase
yield was to find a way of supplying extra nitrogen, phosphorus and
potassium to the soil. Neither a break crop of legumes, nor manure was the
answer, since both demanded precious acres to produce. The search for
fertiliser took unexpected turns. British entrepreneurs scoured the old
battlefields of Europe searching for phosphorus-rich bones. In about 1830
a magic ingredient was found: guano. On the dry seabird islands off the
South American and South African coasts, immense deposits of bird
droppings, rich in nitrogen and phosphorus, had accumulated over
centuries. Guano mining became a profitable business, and a grim one. Off
South-West Africa, the discovery in 1843 of the tiny island of Ichaboe,
covered in 25 feet of penguin and gannet excrement, led to a guano rush
followed by a mutiny and battles. By 1850, Ichaboe, minus 800,000 tonnes
of guano, was deserted again.

Between 1840 and
1880, guano nitrogen made a vast difference to European agriculture. But
soon the best deposits were exhausted. In the dry uplands of Chile, rich
mineral nitrate deposits were then found, and gradually took the place of
guano in the late 19th century. The nitrate mines fuelled Chile's economy
and fertilised Europe's farms.

On July 2nd
1909, with the help of an engineer named Carl Bosch from the
BASF company, Fritz Haber succeeded in combining
nitrogen (from the air) with hydrogen (from coal) to make ammonia. In a
few short years, BASF had scaled up the process to
factory size and the sky could be mined for nitrogen. Today nearly half
the nitrogen atoms in the proteins of an average human being's body came
at some time or another through an ammonia factory. In the short term,
though, Haber merely saved the German war effort as it was on the brink of
running out of nitrogen explosives in 1914, cut off from Chilean nitrates.
He went on to make lethal gas for chemical warfare and genocide.

On farms, Haber
nitrogen ran into much the same revulsion as had greeted the seed drill.
For many farmers, the goodness of manure could not be reduced to a white
powder. Fertiliser must in some sense be alive. Haber nitrogen was not
used as fertiliser in large quantities until the middle of the 20th
century, and for a good reason. If you put extra nitrogen on wheat, the
crop grew taller and thicker than usual, fell over in the wind and rotted.
On General Douglas MacArthur's team in Japan at the end of the second
world war a wheat expert named Cecil Salmon collected 16 varieties of
wheat including one called “Norin 10”, which grew just two feet tall,
instead of the usual four. Salmon sent it back to a scientist named
Orville Vogel in Oregon in 1949. Vogel began crossing Norin 10 with other
wheats to make new short-strawed varieties.

In 1952 news of
Vogel's wheat filtered down to a remote research station in Mexico, where
a man named Norman Borlaug was breeding fungus-resistant wheat for a
project funded by the Rockefeller Foundation. Borlaug took some Norin, and
Norin-Brevor hybrid, seeds to Mexico and began to grow new crosses. Within
a few short years he had produced wheat that yielded three times as much
as before. By 1963 95% of Mexico's wheat was Borlaug's variety, and the
country's wheat harvest was six times what it had been when Borlaug set
foot in the country.

In 1961 Borlaug
was invited to visit India by M. S. Swaminathan, adviser to the Indian
minister of agriculture. India was on the brink of mass famine. Huge
shipments of food aid from America were all that stood between its
swelling population and a terrible fate. One or two people were starting
to say the unsayable. After an epiphany in a taxi in a crowded Delhi
street, the environmentalist Paul Ehrlich wrote a best-seller arguing that
the world had “too many people”. Not only could America not save India; it
should not save India. Mass starvation was inevitable, and not just for
India, but for the world.

No need to starve

Borlaug refused
to be so pessimistic. He arrived in India in March 1963 and began testing
three new varieties of Mexican wheat. The yields were four or five times
better than Indian varieties. In 1965, after overcoming much bureaucratic
opposition, Swaminathan persuaded his government to order 18,000 tonnes of
Borlaug's seed. Borlaug loaded 35 trucks in Mexico and sent them north to
Los Angeles. The convoy was held up by the Mexican police, stopped at the
border by United States officials and then held up by the National Guard
when the Watts riots prevented them reaching the port. Then, as the
shipment eventually sailed, war broke out between India and Pakistan.

As it happened,
the war proved a godsend, because the state grain monopolies lost their
power to block the spread of Borlaug's wheat. Eager farmers took it up
with astonishing results. By 1974, India's wheat production had tripled
and India was self-sufficient in food; it has never faced a famine since.
In 1970 Norman Borlaug was awarded the Nobel Peace Prize for firing the
first shot in what came to be called the “green revolution”.

Borlaug had used
natural mutants; soon his successors were bringing on mutations
artificially. In 1956, a sample of a barley variety called Maythorpe was
irradiated at Britain's Atomic Energy Research Establishment . The result
was a strain with stiffer, shorter straw but the same early harvest and
malting qualities, which would eventually reach the market as “Golden
Promise”.

Today scientists
use thermal neutrons, X-rays, or ethyl methane
sulphonate, a harsh carcinogenic chemical—anything that will damage
DNA—to generate mutant cereals. Virtually every
variety of wheat and barley you see growing in the field was produced by
this kind of “mutation breeding”. No safety tests are done; nobody
protests. The irony is that genetic modification (GM)
was invented in 1983 as a gentler, safer, more rational and more
predictable alternative to mutation breeding—an organic technology, in
fact. Instead of random mutations, scientists could now add the traits
they wanted.

In 2004 200m
acres of GM crops were grown worldwide with good
effects on yield (up), pesticide use (down), biodiversity (up) and cost
(down). There has not been a single human health problem. Yet, far from
being welcomed as a greener green revolution, genetic modification soon
ran into fierce opposition from the environmental movement. Around 1998, a
century after Crookes and two centuries after Malthus, green pressure
groups began picking up public disquiet about GM
and rushed the issue to the top of their agendas, where it quickly brought
them the attention and funds they crave.

Wheat, because
of its unwieldy hexaploid genome, has largely missed out on the
GM revolution, as maize and rice accelerate into
world leadership. The first GM wheats have only
recently been approved for use, their principal advantage to the farmer
being so-called “no till” cultivation—the planting of seed directly into
untilled soil saves fuel and topsoil.

Soon after
Norman Borlaug went to India in 1963, a remarkable thing began to happen.
The world population growth rate, in percentage terms, had been climbing
steadily since the second world war (bar a two-year drop in 1959-60 caused
by Mao Xedong). But in the mid 1960s it stopped rising. And by 1974 it was
falling significantly. The number of people added each year kept on rising
for a while, but even that peaked in 1989, and then began falling
steadily. Population was still growing, but it was adding a smaller and
smaller number each year.

Demographers,
who had been watching the exponential rise with alarm, now forecast that
the population will peak below ten billion—ten gigapeople—not long after
2050. Such a low forecast would have been unthinkable just two decades
ago. Already, in developing countries, the number of children born per
woman has fallen from six to three in 50 years. It will have reached
replacement-level fertility (where deaths equal births) by 2035.

This is an
extraordinary development, unexpected, undeserved—and apparently
unnatural. Human beings may be the only creatures that have fewer babies
when they are better fed. The fastest-growing populations in the world
over the next 50 years will be those of Burkina Faso, Mali, Niger,
Somalia, Uganda and Yemen. All except in Yemen are in Africa. All are
hungry. All remain untouched by Borlaug's green Revolution: all depend on
primarily organic agriculture.

In 10,000 years
the population has doubled at least ten times. Yet suddenly the doubling
has ceased. It will never double again. The end of humanity's population
boom will happen in the lifetimes of people alive today. It is the moment
when Malthus was wrong for the last time.

Of course
feeding ten billion will not be trivial. It will require at least 35% more
calories than the world's farmers grow today, probably much more if a
growing proportion of those ten billion are to have meat more than once a
month. (It takes ten calories of wheat to produce one calorie of meat.)
That will mean either better yields or less rainforest—which is why
fertilisers, pesticides and transgenes are the best possible protectors of
the planet. The story of wheat is not finished yet.